Automatic train-control system



W. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM Original Filed April 1, 1916 5 Sheets-Sheet 1 B L Q Q t E K L,

A a; I

5k V l Q n L l N I nwmroe w W W I \0 0 :1- By -91! "3 \1 F G ATTORA/EV ApriI 6 1926;

' W. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM Original-Fil April 1, 1916 5 Sheets-Sheet 2 29 FIG. 2

95 11 3 [0/ QALSJ INVENTOI? 1. z. 5 ATTORNEY EEBQWS April 5 9 1926.

w. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM I 5 Sheets-Sheet 5 Original Filed pril 1, 1916 RMM mi 3 April 6 1926. 1,580,105

W. K. HOWE AUTOMATIC .TRAIN CONTROL SYSTEM Original Filed April 1, 1916 5 Sheets-Sheet 4 April 6, 1926. 1,580,105

w. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM Original il pril 1, 1916 5 Sheets$heot 5 ATTORNEY WINTHROP K. EUWE, 0E ie'tfiCHESTEEL, YQTEt-K, ASESXGNQR TO GENERAL RAILWAY lG-NAL 2;, 0E GATES, NEW YQFJK, CGETPQRATION OE EIEW 'YQRK.

AUZEEQIEATIG TEJQIN-GQEZTELUL Application filed April 1, 1916, serial Rio. 8236* To all whom it may concern:

Be it known that l, Wm'rrrnor K. Hows, a citizen of the United States, and a resident of the city of Rochester, in the county of Monroe and State of New York, have invented a new and useful Automatic Train- Control System, of which the following is a specification.

This invention relates to systems for automatically controlling the speed of railway trains so as to facilitate the movement of trafic on railroads without sacrificing safety In order that a system. for automatically controlling the speed of railway trains may be applicable tothe ditierent conditions found in practice, it is desirable, for reasons quite generally understood and appreciated by those skilled in the art of railway signaling, that the system should provide for automatically governing the speed of a train to correspond to the speed which it should have if the conditions are such that the train should reduce its speed and proceed cautiou ly, whether this reduction in speed is required by the presence of another train ahead, a sharp curve or dangerous grade, or the like. Also, the system should preferably be constructed so that itoperates in accordance with principles and practices which are economical and safe; and in this connection it seems important to follow the principles andpractices Which have been found by long trial and experience in railway signaling to satisfy the exacting requirements of this kind-sf signaling. According to one of these principles which is generally used in railway signaling at the resent time, and which has been adopted in this invention, although it is appreciated that certain features of the invention do not necessarily require the use of this principle, the track is divided into electrically isolated sections or blocks, each provided with a source 0 current and a relay or translating device; and the source of current and the relay are so connected with the trackrails of the corresponding section as to constitute a normally closed track circuit, this track circuit serving as a reliable means for detecting the presence of a train on a iven portion of the track. Inapplyingt is principle of the normally closed trackcircuit to a system for automatically controlling, railway traffic, it is necessary to recognize the fact, which is well known by Renewed may a, 1921. Serial No. 468,216.

those skilled in the art of railroad signaling, that, in order to facilitate and expeelite traffic, the blocks or track sections into which the track is divided in practice vary in length; and it is necessary that a system for automaticallycontrolling railway traftic, before it can be applicable to present day conditions, must make proper allowances for this variation in the length of blocks or track sections. i

A- further condition found in practice for which it is desirable .to make provision is that found at places where traiiic is liable'to become congested, as for instance at a station WhQIQ passenger are taken on and let of, under these con ions it being desirable to permit trains to run closer together or to close up, providing they reduce t-heir'speed correspondingly.

Another condition which should be considered. in designing a system for antomati cally controlling the speed of railway trains, is found principally at places, such as yards, crossings and the like, Where the routes of different trains conflict, it being necessary in this case to make proper provision for bringing a train automatically to an absolute stop ifit would interfere with the route of another train in continuing its movement. 1

With these considerations in View, this invention has for its objects to devise a simple and novel system for automatically controlling the speed of railway trains which will satisfy the conditions found in prac-- tice, such as those hereinbefore explained, and also to construct and arrange-the parts of this system so that it will perform its necessary functions efiiciently and reliably.

Other objects and advantages will appear as the description of the invention progresses; and the novel features of the invention are pointed out in the appended claims.

lhe invention primarily consists in the parts, tions of parts, and in the electrical connections and controlling circuits for said parts, all of which will be more fully set forth hereinafter.

The specific system disclosed herein is an improvement upon the system disclosed and claimed in my prior application Ser. No. 38,132, filed July 0, 1915.

V In describing the invention in detail, refin the arrangements and combinaerence will be made to the accompanyin drawing in which is illustrated one preferre physical embodiment of the invention, in

which like references to characters refer to like parts in the several views, and in whic r Fig. 1 is the diagrammatic illustration of an assumed lay-out of railroad track which has been selected to bring out the conditions with which this invention more particularly deals; Fig. 1 also showing the blocks or track sections, the control ramps or contact rails, selector ramps or tappets, the limits of control of each control ramp and the curves of permissive speed, all of which are more fully explained hereinafter. V

Fig. 2 shows the parts of the system which are carried by.the vehicle or train, together with their electrical connections and their control circuits, these parts being shown diagrammatically more with a view to making their functions and operations more easily understood than with regard to their exact construction and arrangement;

Figs. 3 and 4 are diagrammatic views of the parts of the track shown in Fig. 1, showing the control devices and their electrical connections of the parts of the system 10- cated along the track, the left hand end of Fig. 4 being a continuation of the right hand end of Figure 3;

Fig. 5 is thesame as Fig. 2 with the emergency brake control omitted; and

Fig. 6 is. the same as Fig. 3 with the control wires and contacts for applying low voltage to the ramps omitted so as to provide trackway equipment suitable for governing the modified form of car apparatus shown inFig. 5. 7

Referring to the accompanying drawings,

in Fig. 1 is illustrated two stretches of straight track T and '1 connected by re versecurves, also a third stretch of track T which intersects the stretch of track T near cated a station, and that the switch connecting the stretch of track T with the stretch of track T and the signals M and N govern ing the movements of trains over these stretches of track are controlled in the usual manner by an interlocking machine located in the tower W. It should be understood that Fig. 1 illustrates merely an assumed lay-out which .is selected because it appears to bring out clearly the different features and characteristics of the invention, and that the invention is in no wise restricted tothe particular arrangement of the stretches of track, curves, location of station, etc. but is applicable to various other arrangements and combinations.

One of the track rails 2 of the stretches of track T and T and the connecting curves is divided by insulating joints 3 into track sections or blocks, designated A to J inclusive. These blocks may be of any length necessary to obtain the desired spacing of trains, but in practice these blocks preferably would not be exactly of the same length, for reasons well known to those skilledin the art of railway signaling and more fully explained hereinafter. For the purpose of rendering more intelligible the features of construction and operation of the system embodying this invention, without unduly complicating the illustration and description, it is assumed that the combined length of the blocks B and C, of the blocks F and G, of the blocks G and H and of the blocks H and I is substantially equal to the length of the'block A; whereas each of the blocks D and E are: shorter than the block A. It is to be understood, however, that the particular successive occurrence of the different length blocks illustrated is not compulsory and that the invention is in no way restricted to the particular arrangement and lengths of blocks illustrated, since several blocks of the samelength may follow each other and then any number of longer blocks or shorter blocks arranged end to end or overlapping, and so on in any sequence or combination. The normal direction of traflic over the stretches of track T and T is indicated by an arrow marked Trafiic. 7

Associated with each track section or block, A to 'J inclusive, is a ramp or contact rail R, the; ramps for the different blocks being designated BA, BB, and so on, and being preferably located at the entrance to the corresponding block. These ramps are of any suitable construction or of any desired length, and maybe located on either] 7 that a contact shoe or similar device carried by the train may make electrical contact with these ramps and also be operated mechanically by engagement with said ramps.

Limits of control of the ramps.

The limits of control of each of the ramps RA RB and so on, are indicated in Fig. 1 by horizontal lines extending between certain vertical lines extending downwardly from the insulating joints 3 at the entrance to each block and designated a, b, and so on, each of these horizontal lines indicating the limits of control being connected at one end by a dot to one of the vertical lines a, b, and so on, and terminating at its other end in an arrow. For example, the limit of the control of the ramp BB is from the insulating joint 3 at the entrance of the block B to the insulating joint 3 at the entrance of the block D; and this limit of control indicates that Whenever either of the blocks B or C is occupied by a train, the ramp RB should braking curve be in the condition to have-an efiect on the speed control apparatus of the train corre- A Curves of permissive speed. Below the horizontal lines hereinbefore described, which indicate the limits of control of different ramps R, are a series of curves which indicate permissive speeds at different points along the stretch of track T and T These curves are drawn in accordance with the well known method of plotting speed and distance curves to rectangular coordinates, and are derived from the braking curves of the kind'of train equipment traveling over the railroad. In case there are different kinds of train equipment having different braking curves, it is desirable for safety to arrange the block lengths and the curves indicating permissive speeds, so as to properly protect the heaviest and fastest train which may run on the railroad.

A brief explanation of the curve of per missive speed may serve to make it easier to understand the relation which these curves bear to the entire'system. In thesecurves the horizontal distances represent the distance' of travel of the train over the successive blocks to any arbitrary scale, which in eneral, with the particulan exception of the locks D and E corresponds in scale with that to which the blocks A to J are drawn; and vertical distances represent permissive speeds to an arbitrary scale of eed in miles per hour,.or in any other suitab e units.

The lower horizontal line 4 represents zero speed, and the horizontal line 5 represents some predetermined low speed such as five miles per hour, or ten miles per hour, or some other arbitrary figure which seems best adapted -to the particular con-- ditions of the railroad in question. The curves of permissive speed for, the different blocks or combinations of blocks are based .on the same principles, and the description of one will suffice for all. Referring to the block A, the curve 6 (the curve drawn as a full line) represents, for each point in the length of the block A,the permissive speed at that point. Generally speaking thisg rve-6is equivalent tothe for the fastest and heaviest train which the system is'de'signed to protect,

clue allowances being made for the hysical characteristics of; the'block A,"suc1 as its grade, curves or other factors affecting the braking distance of the train. It will be noted that this curve 6 intersects the line 5 indicating the predetermined low speed, in

this case assumed to be ten miles per hour, at a short distance from the end of the block it is assumed that the speed control system embod ing this invention does not automatically ring the train to a complete stop at the end of each block but only to the predetermined low speed. The distance between the point, where the curve 6 intersects the line 5 of the predetermined low speed, to the vertical line b at the end of block A,

may be of any length desired, and is adopted principally as a factor of safety.

The significance of the-curve 6 may bebet- 'ter understood by some illustrations; and for assume that the train enters block instance, A ata speed of approximately fifty-five miles per hour, and that another train occupies block B. Under these conditions it, can

be seen from the curve 6 that the first mentioned train entering block A should have the brakes immediately applied-in order that this train may be brought to a predetermined low speed bythe time it reaches the end of the block A. ,Suppose, however, that a train enters theblock A' at the speed of about thirty miles per hour, and that the block B is occupied by another train; then, under these conditions the first mentioned train entering the block A need not commence to reduce its speed immediately, but may pro-' ceed some distance into the block Abefore its brakes have to be applied, this distance being readily determlned bycontinuing the horizontal line corresponding to the speed of this train and finding out where thls horizontal line intersects the curve 6, due. allowance being made for time required for the application of the brakes and for the brakes to attain their full braking effect.

For the next illustration, assume that when atrain enters the block A, neither of the blocks B no.1 C is occupied by another train; then underthese conditions the .first train entering the block A is not required to reduce its speed while traveling through the block A, and may attain any speed consistent with safety; The safe speed which the train may attain in the block A depends upon the special local conditions, which 'may permit comparatively high speed or may require .comparativelylow speed. Furthermore, the speed which it is safe for the train in the block A to travel must not be so great that, when it enters the block. B-, it will be traveling to'o fastto be brought by its brakes to the predetermined low speed by the time it reaches the-end of the block C, since it may well happen that while neither of the blocks B nor C'is occupied by a train. anothei' train may occupy the block D and be located just ahead'of the insulating joint 3 at the entrance of the block D. For these reasons it is contemplated according to this invention to make provision for limiting the maximum speed which a train may attain in the block A, even though the trafiic conditions permit the train to proceed-at full speed through the block A. This limitation upon the permissive maximum speed of a train under a proceed signal is ob 'tained by reason of the construction and arrangement of certain parts of the system carried on the train, as explained more fully hereinafter, and these parts operate providing a train in the block A attains a speed greater than that indicated by the horizontal dash line 7, it being possible, however, for a train to travel through the block at any lower speed. The curves of permissive speed shown in Fig. 1 and described briefly hereinbcfore, may be derived from the braking curve of the heaviest and fastest train traveling on the railroad, either for an emergency application of the brakes, or fog so-called service application of the brake-s .n f r any other suit able application of the brakes, as may be desired; and it should be understood that these curves of permissive speed illustrated in Fig. 1 are not intended to be quantitatively precise but merely represent certain assumed conditions.

Oomtmctz'on of parts located along the track.

Referring to Figs. 3 and 4:, at each end of each block A to J inclusive, preferably at the exit end, a track battery 8 is connected across the track rails 1 and 2; and at the other end of each block a track relay 9 is connected across the track rails 1 and 2. The track battery 8 and track relay 9, together with the track rails 1 and 2 of the corresponding block, constitute the well known normally closed track circuit, the operation of which will be clear to those skilled in the art of railway signaling Without further explanation. The track relays 9 are provided with armatures or contact fingers illustrated according to established convention, some of said relays having two armatures and others four armatures; and for simplicity the track relays of the blocks B, C and so on, and their corresponding armatures, are given the same reference characters as the track relays and its armatures of the block A, with the distinctive exponentsq, 2 and so on added thereto. The armatures of the track relays9 control circuits for connecting sources of current of different intensities, in this instance shown as batteries 14, 15 and 16, across the ramp at the entrance to the corresponding block and one of the track rails, as the track rail 1; but the different electrical connections between the ramps and the armatures and cooperating contacts of the track relays 9 will not be set forth in detail, since the different controlling circuits will be more fully explained hereinafter.

Located along the trackway, preferably between the track rails 1 and 2, are suitable selector ramps, designated SR, SC 8L, and these selector ramps are located at different distances from one of the track rails in order to determine the particular selection obtainable by a particular group L of selector ramps. These selector ramps act like cams or similar devices to actuate mechanically cooperating shoes or tappets carried by the train; and to perform this function, said selector ramps may be supported in any suitable way, preferably resiliently, and are so shaped with sloping ends as to engage the selector shoes carried by the train with the least amount of shock and wear. Also, these selector ramps may Construction of parts carried on the train.

Referring to Fig. 2, the train or vehicle is illustrated diagrammatically as comprising two pairs of wheels and their coninectin axles, designated 17-18, 2021, and 19 and 22 respectively, it being understood that the axles 19 and 22 will in practice be connected by some suitable frame. The devices on the train for establishing the permissive speeds at different points in its travel, and also for establishing its actual speed, are connected by suitable gearing to one of the axles of the train, preferably to an axle attached to wheels which are neither driven nor braked. In the particular construction illustrated, a

norm 23 is secured to the front axle 22 in mesh with a worm gear 24 secured to the lower end of a shaft 25, said shaft 25 being mounted in suitable bearings (not shown). Secured to the upper end of the shaft 25 is a beveled gear 26 which meshes with a mating beveled gear 27 fixed to a shaft 28, said shaft 28 being journaled. in suitable supports or bearings 29 and 30. Fixed to the shaft 28 is a bifurcated member 31, and pivoted to the outer end of each of the bifurcations of said member 31 is a weighted arm having integral therewith a toothed sector 33. Mounted on the shaft 28 to turn there with and so as to be capable of longitudinal movement thereon, and also relative to the bearing support 30, is a sleeve 34 which has on opposite faces thereof teeth adapted to mesh with the teeth of the sectors 33. This sleeve 34. has secured thereto at its lefthand end two spaced collars 35, and interposed between the outer collar 35 and an enlarged head 36 on the shaft 28 is a compression coil spring 37. Below the shaft 28 and the sleeve 3i carried thereon is a shaft 38, which is cams 54 and disposed in a plane substantially at right angles to the plane of said shaft 28, said shaft 38 being journaled in suitable supports 39 and 40. Fixed to one end of the shaft 38 is an arm 41 extending upwardly; and the upper end of this arm 41 is furcated and straddles the sleeve 34 between the collars 35, suitable pins OIJ'OllGIS 42 being secured in the bifurcations of said arm and extending into the space between the collars 35. Secured to the shaft 38 are two downwardly projecting curved arms 43 and 44 having contact studs 45 secured to their lower ends, but insulated from the body portions of said arms. Loosely mounted on the shaft 38 adjacent to each of the arms 43 and 44 is an arm or lever, desig nated 46 and 47, the'upper end of which is provided with a freely revoluble roller 48, and the lower end 49 of which extends downwardly into position to make contact with the contact stud 45 of the corresponding arm 43 or 44, as the case may be; and the downwardly projecting extension 49 of each arm 46'and 47 isconnected to the corresponding arm 43 or 44, as, the case may be, by a tension spring 50.

Arranged substantiall parallel with the shaft 38 is a shaft 51 journaled in suitable bearings or supports 52 and 53; and secured to this shaft 51 are-two cams 54 and 55, each disposed in the plane of one of the arms 46 or 47. These cams 54 and 55 are so arranged that when the shaft 38 and the arms 46 and 47 carried thereby, are rocke in a clockwise or counter-clockwise direction, the rollers 48 carried by said arms engage said cams at a point, indicated at :12. These cams 54 and 55 are shown as symmetrical about a line extending from the point w through the center of the shaft 51,

'so that a rotation of the shaft 51 and the cams 54 and 55, either clockwise or counterclockwise from their normal or neutral position, shown in Fig. 2 will produce substantially the same movementof the cooperating rollers 48. In other words, since the are symmetrical, the same effect is produced when the vehicle is traveling in either direction. The function of the cams 54 and the relation which they bear to the curves of permissive speed, hereinbefore referred to, willbe pointed out more fully hereinafter in a'description of the operation. One end of the shaft 51 extends to a point approximately in the plane of the shaft 28, and secured to this end is a gear wheel 56. The shaft 51 is biased by suitable means to assume an initial position, corressponding to that shown in Fig. 2; and in the simplified construction illustrated, this bias is produced by a counterweight 56 suitably attached to the gear 56 so as to be directly under the shaft 51 when said shaft is in the desired initial position. The gear 56 is also provided with a small cut-away portion 56 for the purpose hereinafter explained. Above the gear wheel 56 is a shaft 57, having secured thereto a worm wheel 58 adapted to mesh with the teeth of said gear wheel 56; and this shaft 57 is connected to this head 36 of the shaft 28 by a universal coupling 59 of suitable construction, so that the shaft 57 may move up and downto bring the worm gear 58 out of and into engagement with the gear wheel 56 without interfering with the rotation-of the shaft 57. On the outer end of the shaft 57 is loosely mounted a collar or bearing 60; and arranged above this collar is a solenoid 61, having a core 62. The lower end of the core 62 is bifurcated and straddles the collar 60, each of the bifurcations of said core beingpivotally connected to said collar 60 by a pm 63.

A contact shoe is carried by the train-din any suitable way I in position to cooperate with the ramps R, and in the particular construction shown, this contact shoe is illustrated diagrammatically as mounted upon a bracket 64, which for simplicity is assumed to be of insulating material and which is suitably mounted upon one of the journal boxes of the axle 19. bracket 64 is'a vertically movable plunger 65, which has a. collar 66 secured thereto near its lower end and is pressed downwardly by a compression coil spring 67 interposed between said collar 66 and the under face of the bracket 64. To the upper d end of the plunger 65 is fixed a button 68 material, which, being larger than the p unger 65, engages the upper face of the bracket 64 and limits the down ward movement of said plunger 65. The plunger-or shoe 65 is arranged in substantially the same plane as the ramps It and is designed to make electrical contact with said ramps as the train passes them, and also to actuate a suitable circuit controlling device.- To enable the shoe or plunger 65 to perform this circuit controlling function, a contact spring 69 is secured to the bracket 64 to extend over the insulatof insulatin ing button- 68 of the shoe 65 and is disposed in position to make contact with a contact member 70, also secured to the braoket.64,- when the shoe 65 is in its lower position. When, however, the shoe 65 is raised by engagement with a ramp R, the insulating button 68 strikes the contact spring 69 and raises it out of contact with the contact member 70. v

The selector mechanism which cooperates with the selector ramps to perform certain selecting functions at certain points in the travel of the train may be of -any suitable construction, but is shown diagrammatically as comprising a plate or panel 71, assumed'to of insulating material, which is fastened Mounted on the cured to the panel 71 are two lugs or. ears 72 which support a rod or shaft 73; and mounted loosely on this rod 73 are three selector tappets, designated 74, 75 and 76, these selector tappets being capable of rocking up and down on the rod 73independently of each other, and being provided with suitable means (not shown) which prevents movement of said tappets lengthwise of the rod 73. The downward position of said tapp'ets is determined by suitable means shown in the simplified construction as a cross bar 72 fastened to the lug 72 and extending under the tappets- The actuation of the'selector tappets 74, 75 and 76 by the corresponding selector ramps SR, SC or SL,

may bring about the selection in any way,

either mechanically or electrically, but in the particular construction illustrated the selector tappets, are provided with upwardly extended contact arms, designated 77, 78 and 79, which are arranged to move into and out of contact-with suitable contacts, indicated diagrammatically by arrows. The opening and closing of certain electric circuits by the actuation of the selector tappets 74, 75 and 76 causes an energization or deenergization 'of certain electromagnets or relays, hereinafter termed selector relays, two of which are shown in Fig. 2 and designated 80 and 81. These selector relays 80 and 81 are revided with suitable circuit controllers, w ich are represented in the drawing according to established convention and which are designated 82, 83 and 84, 85 respectively.

The apparatus of the system carried on the train is controlled by two car relays K and S, having armatures 86,87, 88 and armatures 89, 90, respectively, the control relay K serving to control the operation of the part of the apparatus which controlsthe speed of the train, and the stop relay S-controlling the parts of the apparatus which operate to bringthe train to an absolute stop.

The speed control system embodying the invention may be used with or without fixed signals located along the track; but in the embodiment, of the invention illustrated cab signals are iven aboard the train by colored lights, t e green lamp G being lighted to indicate roceed, and the yellow lamp Y being lig ted to indicate caution.

For this automatic train control sys tem it is assumed that the train or vehicle is equipped with the ordinary type of pneumatic brakes, which includes the usual train pipe 91. Since the construction and o eration of the pneumatic system o brakes is well known, it is deemed unnecessary to show and describe the construction and operation of this system in detail, it being sufiicient =for a clear understanding of this system to know that the brakes are automatically applied on the train when the train pipe 91 is vented, and that the distinction as to whether or not an emergency'application or a service application of the brakes occurs ordinarily depends upon the rapidity with which the train pipe 91 is vented. The venting of the train pipe 91 at different rates to obtain either an emergency application or a service application of the brakes may be obtained in different ways, but in the diagrammatic illustration shown, the train 'pipe 91 connects to two electrically operated valve mechanisms, designated EB and SB. It is deemed unnecessary to enter into a detailed illustration and description of the construction and operation of these electrically operated valves EB and SB since various devices, capable of accomplishing their necessary functions, are well known in the art, it being sufiicient for the present purposes to understand that the deener ization of the electrically operated valve B causes a venting of the train pipe 91 sufficient to cause a service application of the brakes, and in the same way a deenergization of the electrically operated valve EB causes an emergency application of u the brakes.

In Fig. 2 a ramp R is shown in position to cooperate with the plunger or shoe when the train advances; but, instead of controlling, bymeans of track relays, the difference of potential established between this i amp R and a track rail 2 by the batteries '93, 94 and 95, a switch 96 is arranged, fof'simplicity, to engage certain contact studs 97, 98 and 99, which are so arranged that when the switch 96 is in contact with the contact stud 97 the combined potential difference; of the batteries 93, 94 and 95 is established between the track rail 2 and the ramp R by a circuit as follows: starting at the track rail 2, conductor 100, batteries 93, 94 and 95 in series, conductor 101, contact stud 97, switch 96 and conductor 102 to the ramp B. When the switch 96 is moved into contact with the contact stud 98 the combined difference of potential of only two of the batteries 93 and 94 is estab lished across the track rail 2 and the ramp R by a circuit which can be easily traced by analogy to the circuit just above traced, and in the same way when the switch 96 is in contact with the contact stud 99 a difference of potential equal to only one of the batteries 93 is established between the track rail and the ramp B. These potential differences of different intensities will be hereinafter referred to as high, medium and low differences of poential.

Operation in general.

Before setting forth in detail the operation of the different parts of the system embodying this invention and befo're tracing the train is about conditions exist in .eration of the system is about to enter each This operation is,

the diiferent circuits, it seems instructive to ronsider briefly a general outline of the op-- together with the prin- 'cipal functions performedby the parts of the system. As 'a train a preaches each block, or a number of bloc shaving substantially the same physical characteristics, as length, grade, curves and the like, the train passes over a number of selector ramps SC, SR or SL, which are arranged in a predetermined wa between track rails so as to effect certaln successive movements of the selector tappets 74, 7 5 or 76 to energize and maintain energized one of the selector relays 80 or 81, so that the speed of the train in the block. or blocks next entered will be controlled by the cam corresponding to the selector relay energized. Then, as the train block'and the. first contact shoeon the train strikes the ramp R at the entrance to that block, automatic control of the speed of the train is provided for by certain circuits and movements of parts, in general as follows:

First, the parts of the system controlling the speed ofthe train,'in case thetrain has been running under dominance of this speed control apparatus,-.are restored to their nor- 4 mal or idle position, so that it relieves the train from the limitations upon its speed to which it has been previously subjected. however, de endent upon traffic, conditions in the-bloc into which to enter,-and if danger this block, the parts are not reset or restored to their normal position, but remain in the position they have'at the time, the result being that the train, if itenters this next block,

' speed hereinbefore mentioned.

I Second, when axle enter a block, as the block B, assnmin is extingu the caution signal is lighted, and then later,

- and that the parts of the speed control apparatus have already'been restored to'their normal position, this speed control apparatus is made subject to the trafiic conditions of the next block in advance, as the block D, so that, if this block D is occupied, the green lamp G givin the proceed signal ished, the yel ow lamp Y giving when the combined'conditions of the actual speed of the train and its distance from the oint of danger are such that the brakes should be applied, the cooperation of the cam 54 or the cam 55 and the speed indicating device or governor causes the automatic application of the brakes. However, if no danger conditions exist in this next block I in advance, as the block D, the parts of the speed control apparatus are retained in their normal or idle position and permit the train to proceed without'any restriction upon the must do seat a" speed lower than the predetermined low the first pair of Wheels and;

Y may attain, except that it may not exceed the predetermined maximum speed limitation for the block it is in. i

There are other features of the operation of the system embodying this invention which are not included. in the above general description of the operation, but these particular features will be made clear therein--v after. 1

In describing the operation, occasion will be had to refer to different controlling cir- 'euits from time to time and for simplicity and also to avoid unnecessary repetition, these controlling circuits as they are described and traced will be given designating speed which it numbers and will thereinafter be referred to by these numbers. Because of the number of circuits'involved, a reference table, giving the number of'eac h circuit and a brief statement of the function performed by that-circuit, is given as follows:

9 33;: Function One Normally energizes the control relay K. Two Gives the proceed signal by lighting the green lamp G.

Normally energizes the cam starter magnet 61.

Four Normally energizes the sto relay S.

Five Normally energizes theva ve EB controlling the emergency brakes.

Six. Preliminarily energizes the selector relay 81.

Seven. Maintains the selector relay 81 energized.

Elght Energizes valve SB controlling the service brakes when the selector relay 81 is eflective. I

Nine Prelimlnarily energizes selector relay 80.

Ton. Maintains selector relay energized.

Eleven Energizer valve SB controlling the service brakes when the selector relay 80 is energized.

Twelve.-. Maintains the control relay K energized when the shoe is on an energized ramp.

Thirteen Maintains the stop relay 8 energized when the shoe is on an energized ramp.

l'ourtoan Gives the caution signal by lighting the yellow lamp Y.

Operation of'the parts 0f the system on the train.

The parts of the system embodying this invention which are carried on the train are shown in Fi 2 in the normal or idle position in'whic speed lower than the predetermined maximum s eed for the block it IS occupying at the time. The operation of rep acing or restoring these parts to their normal or idle iti'onafter they have been operated will e' taken up later in the description of the operation. When the parts of the system are in their normal or idle position the control'relay K is normally energized by current supplied from a local source of current carried by the train, as the battery 92, along a circuit which may be traced as follows Uircm't Number One.

From the battery 92, conductors 105, 106, 107, 108, 109, and 111, armature 86 of the c ntrol relay K in its upper position, condi ctors 112 and 113, control relay K, conductors 114, 115 and 116, contact member 70,

the train may proceed to any till 'I no contact spring 69, and conductors 117, 118, 119 and 120 back to battery 92.

\Vhen the control relay K is energized and its armature 88 is in its upper position, the green lamp (1 is lighted by a circuit which may be traced as follows:

Circuit Number Two.

From the battery 92, conductors 10.), 106.

' 107, 108, 109 and 12 1, armature 88 ot the control relay K in its upper position, conductor 122, green lamp (,1, and conductors 123, 124, 125 and 120, back to the battery 92.

Also, when the control relay K is ener gized and its armature 87 is in its upper position, the cam starter magnet 61 is supplied with current from the battery 92 flowing in a circuit which may be traced as follows:

Circuit Number Three.

From the battery 92, conductors 105, 106, 107, 108, 109, 110 and 126, armature 87 ol' the control relay K in its upper position, conductors 127, cam starter magnet 61, and conductors 128, 124, 125 and 120, back to battery 92.

lVhen the parts of the system are in their normal position, the stop relay S is normally supplied with current from the battery 92 flowing in a circuit which may be traced as follows:

Circuit Number Four.

energized by a circuit which may be traced as follows:

Circuit Number Fi've.

From the battery 92, conductors 105, 106, 107 and 133, armature 90 of the stop relay S in its upper position, conductor 134, electrically operated valve EB and conductors 135, 119 and 120, back to the battery 92.

It is assumed that the parts of the system on the train are shown in Fig. 2 in the 1positions which they assume after the train as passed suitable selector ramps SC and SR which have prepared the speed control apparatus for controlling the speed of the train as it enters the block A, or a block having the same physical characteristics. When the train passes these selector ramps, the selector tappet or shoe 76 is raised to the position where its contact arm 77 closes the circuit for energizing the selector relay 81, which circuit may be traced as follows:

Circuit Number Sir.

From the battery 92, conductors 105 and 136 to the rod 73 on which the selector shoe 76 is mounted and with which it makes electrical contact, thence .along the contact arm 77 of said selector shoe 76, conductors 137 and 138, selector relay 81, conductors 139, 140, 141, 142, 118, 119 and 120, back to the battery 92.

The last traced circuit (Number 6) energizes the selector relay 81 and actuates its armatures 84 and 85 to their upper position, as shown in Fig. 2. lVith the armature 84 of the selector relay 81 in its upper position, and with the middle selector shoe 7.) in its lower or normal position, a circuit for maintaining the selector relay 81 energized is established as follows:

Circuit Number Seven.

From the battery 92, conductors 105 and 136, rod 73, middle selector shoe 75, contact arm 78, conductors 143 and 144, armature 84 of the selector relay 81 in its upper position, conductors 145 and 138, selector relay 8 1, and conductors 139, 140, 141, 142, 118, 119 and 120, back to the battery 92.

When the selector relay 81 is energized, the speed of the train is determined by the cam 55, and electrically operated valve SB, which controls the service application of the brakes, is normally energized to prevent occurrence of the service application of the brakes by a circuit controlled by the cooperation of the cam 55 and the speed arm 46, said circuit being as follows:

Circuit Number Eight,

From the battery 92, conductors 105, 106, 146, electrically operated valve SB, conductors 147 and 1 48 extension 49 of the lever 46, contact stud 45 carried by the arm 43, conductor 149, armature 85 of the selector relay 81 in its upper position, and conductors 150, 142, 118, 119 and 120, back to the battery 92.

In case right hand selector shoe 74 had been raised instead of the left hand selector shoe 76, as would be the case when the train passes a selector ramp SL, the selector relay 80 would have been energized to make the speed of the train subject to the control of the cam 54, the circuit for energizing the selector relay 80 when the selector shoe 74 is raised being as follows:

Circuit Number Nine.

From the battery 92, conductors 105, 136, rod 73, selector shoe 74, and its contacting arm 79, conductors 151 and 152, selector relay 80 and conductors 153, 140, 141, 142, 118, 119 and 120, back to battery 92.

- The selector relay 80 is maintained energized, after it has once been energized, so. ong as the middle selector shoe is in its lower position, by a circuit analogous to circuitNumber Seven, hereinbefore traced, said maintaining circuit of the selector relay 80 being as follows:

Ger-wit Number Ten.

From the battery 92, conductors 105 and 136, rod 73', middle selector shoe 75 and its contacting arm 78, conductors 143 and 154 Circuit Number Eleven.

From the battery 92, conductors 105 and 146, valve SB, conductors 147 and 156, extention 49 of the lever 47, contact stud 45 of the arm 44, conductor 157, armature 83 of the selector relay 80 in its upper position and conductors 158, 141, 142, 118, 119 and 120, back to the battery 92.

Assume thatthe parts of the system carried by the train are in their normal position, as shown in Fig. 2, and that the contact shoe 65 engages a ramp R between which and a track rail, as 2, a high difference of potential exists, such as is the case when the switch 96 is in the position shown in Fig. 2. When the contact shoe 65 en gages the ramp R two effects are produced: first, the shoe is lifted mechanically and breaks the electrical connection between the contact member and the contact spring 69; and, second, the contact shoe'65 makes electrical contact with the ramp R. The mechanical movement of the contact shoe 65, and the resulting se aration of the contact spring 69 from the contact member 70, interrupts the circuit Number One and the circuit Number Four which normally energize the control relay K' and "the stop relay S, respectively, so t at unless the current is supplied tothese relays from some other source than the battery 92, these relays will become deenergized and their armatures will drop. Also, since the circuits Nos. One and Four include the armatures 86 and 89 of the control relay K and the stop relay S, respectively, these circuits will not be re-established, after said'relays have once dropped, when the contact shoe 65 leaves engagement with the ramp R and is returned by the spring 67 to its lower or normal position. In this way, the mechanical cooperation of the contact shoe 65 with each ramp R as the train passes that ramp renders ineffective the circuits which normally maintain the control relayK and the stop relay S in their normal or idle condition, so that said relays will "operate to place the train under-the control ofthe respective devices governed thereby at eachramp unless somethi elsehappens to re ta'in said relays in t eir normal or ,idle.

condition.

When the contact shoe 65 makes electrical contact with the ramp R the partial circuit along the track terminatin at the track rail 2 and at the co'rrespon ing ramp R is connected to the terminals of partial circuits simultaneously'governing the control relay K and the stop relay S, whereby the potential difierence which exists between ed the track rail and the ramp R may causeays to a flow of current through said re maintain them in their normal or idle condition. The complete circuit for the control relay K'is as follows:

O'ircwit Number Twebve.

, Commencing at the-ramp B, through the contact shoe 65, conductors 159, 115 and 114 control relay. K, conductors 113, 160 and 161 to the wheels and axles of the train,

thence to the track rail 2, along conductor through the batteries 93, 94 and 95 in series, conductor 101, through the switch 96 closed on contact stud 97, and along conductor 102 back to the ramp R.

The circuit for energizing the stop relay S by current derived from the batteries along the track is analogous to the circuit above traced for the control relay K and is as follows:

7 Circuit Number Thirteen. Commencing at the ramp R, shoe 65, conductors 159, and 132, stop relay S, con-.

ductors 131, 162 and 161, wheels and axles of the train, track rail 2, conductor 100, batteries 93, 94 and 95 in series, conductor 101, switch 96 closed on contact stud 97 and conductor 102 back to the ramp R.

there. In case av medium difierence of po-, tential, equivalent to that of two' of the batteries, 93 and 94 in series, exists between the track rail 2 and the ramp R, as would be'the case when the switch 96 is closed on the contact stud 98, current will be supplied to the control relay K and the stop relay S along circuits substantiallyjhtr same as circuits Numbers Twelve and Thirteen,

and which can be easily traced by analogy to said circuits. This medium dlfi'erence of potential supplies sufficient current to the control relay K to maintain its armatures in their upper posit-ion providing they are already in their upper position; but this current is not strong enough to raise the armatures of said relays from their lower position. This characteristic of the control relay K, whereby it is responsive to currents of different intensities, may be obtained in different ways, well known in the art, and it is deemed unnecessary to show and describe in detail the construction, the proportioning of the windings and counterweights, and other features which enable it to perform this selective function. In case a low difference of potential, equivalent to the battery 93 alone, exists between the track rail 2 and the ramp R, the current flowing through the control relay K is insuflicient to maintain the armatures of said relay in their upper position; and, consequently, when the contact shoe 65 engages a ramp between which and a track rail only a low difference of potential exists, the armatures of the control relay K are dropped. In this connection it is noted that the stop relay S is designed so that the small current derived from the low difference of potential flowing through its coils will maintain its armatures in their upper position, the armatures of said stop relay being dropped only in case there is no difference of potential between the ramp R and a track rail.

From the foregoing it can be seen that when a train passes a ramp connected to the three batteries 93, 94 and 95 in series, that the armatures of both the control relay K and the stop relay S will be restored to their upper position, in case they are in their lower position, or will be held in their upper position if they are in their upper position at the time. Also,.when the train passes a ramp connected to two of the batteries 93 and 94 in series the armatures of the control relay K will be held in their upper position, providing they are already there, but will not be raised from their lower position; and if the ramp is connected to only one of the batteries, as 93, the armatures of the control relay K will drop, while the armatures of the stop relay S will still be held in their upper position. When the train passes a ramp entirely disconnected from any source of current, the armatures of the stop relay S will drop, and likewise the armatures of the control relay -'K, although, under normal operating conditions, the armatures of the control relay K would be in their lower position at the time the train passes a to tally deenergized ramp. I

Referring again to the case where the armatures of the control relay are dropped by the engagement of the contact shoe 65 with a ramp between which and the track rail only a low difference of potential exists, the dropping of the armature 88 interrupts the circult Number Two for lighting the green lamp G and closes a circuit for lighting the yellow lamp Y as follows:

Circuit N umber Fourteen.

From the battery 92, conductors 105, 106, 107, 108, 109 and 121, armature 88 of the control relay K in its lower position, conductor 163, yellow lamp Y and conductors. 164, 125 and 120 back to the battery 92.

In this way the engineer or motorman is advised that he should proceed cautiously and take measures to bring his train to a stop or to a predetermined low speed by the time he reaches the .end of the block he has just entered.

The dropping of the armature 87 of the control relay K interrupts the circuit Number Three which normally energizes the cam starter magnet 61', thereby permittinv the shaft 57 to drop by its own weight and bring the worm gear 58 into mesh with the gear 56. Since the shaft 57 is connected by the universal coupling 59, through the shaft 28, beveled gears 27 and 26, shaft 25 and gears 24 and 23 to the axle 22 of the train, the cam shaft 51 is turned as the train travels along the track exactly in proportion to the distance traveled by the train. The parts are preferably so proportioned that the cam shaft 51 will be turned nearly 180 when the train travels the length of the longest block occurring on the railroad in question. The shape of the cams 54 and 55, as stated hereinbefore, is determined from the curves of *permissive speed for the particular train upon which they are mounted, the curves of permissive speed being in turn derived from the braking curve 'of the train in question. It can be seen from a study of Fig. 1 and a consideration of the explanation hereinbefore given of the curves of permissive speed, that it is possible to determine from these curves a permissive speed for the train at each point in its travel through a block; and the cams 54 and 55 are intended to reproduce the curves of permissive speed for two different blocks of different length and different physical characteristics. In the particular kind of cam shown, the lengths of the radii of the cam represent different permissive speeds, and the angular displacement of said cam from its initial or normal position (shown in Fig. 2) represents different distances traveled by the train,-it being understood that the exact dimensions of the cam are proportional to the quantities which they represent. In short, the cams 54 and 55 represent for different blocks a predetermined functional relation between the speed of a train and the distance traveled by that train. The effective action of the cams 54 and 55 takes place along the line of movement of their respective followers, namely, the rollers .48 of the arms 4% or 47, and this line of movement maybe assumed for practical purposes to be an arc of a circle indicated in Fig. 2 by the dash line 165. The radius of each cam. 55 or 54, to the point. where the line of action 165 intersects the periphery of the cam, represents the permissive speed for the train at the particular point in its travel corresponding to the angle through which the cam has been displaced from its initialposition at that instant. It should be understood that the cams 54 and 55 are shown for illustrative purposes only and that the shapes of the cams shown are not intended to be quantitatively precise. I

The actual speed of the train is represented by the displacement of the shaft 38 from its initial or normal position (shown in Fig.

2), sincethe shaft 28 is turned at a rate proportionate to the speed of'the train, and as the speed of the train varies the weighted arms 32 are thrown outward by centrifugal force against the opposition of the spring 37 more or less so that the position assumed by the collars 35 and the upper end of the arm 41, corresponds to the actual speed of the train at each instant. In Fig. 2 the parts are shown in the position corresponding to zero speed, the spring 37 having forced the sleeve 34 to the right until one of the collars 35 engages the support 30; and as the speed of the train increases {the shaft 38 is turned in a counterclockwise direction, carrying with it the arm 43, which in turn by reason of the spring 50, rocks the lever 46 and moves the roller 48 toward the cam 55. The parts are So proportioned that when the actual speed of the train, represented by the displacement of the arm 46, is nearly as great as the permissive speed of the train at that instant, the roller 48 will be in contact with the edge of the cam 55. As the cam 55 is turned by the gear 56 and the worm gear 58, the radii'of this vcam increase in'accordance with the curve of permissive speed, thereby tending to move the roller 48 to the right.

As the roller 48 is moved to the right, unless thespeed of the train is reduced correspondingly so that the arm 43 may follow the movements of the lever 46, the spring 50 will be extended and the contact stud 45 will be drawn out of electrical contact with the extension 49 of the lever 46, thereby interrupting the circuit Number Eight for energizing the elctri'c-ally opera-ted valve SB controlling the service application of the brakes. In this way, if the actual speed of the train at any movement exceeds the permissive speed allowable for it at that paritcular instant, the service brakes will be'automatically ap plied.

'In the particular embodiment of the inly reduced by the cooperation of the cam and speed responsive device, in the manner already explained, until apredetermined low speed, such as 5, 8 or 10 miles per hour, has been reached, whereupon this predetermined low spged limitation will be maintained until the speed control apparatus is re-set or restored. This provision enables a vehicle, after having its speedre duced to the predetermined minimum while traveling through a block, to continue its movement and enter the next block, if the circumstances render it expedient to do so. The maximum radii of the cams 54 and 55 areselected to impose-this predetermined minimum speed; and toprevent damage to the apparatus and other objectionable results, by a continued movement of the train after the cams have been moved to their extreme minimum speed position, the cut-away portion 56 is provided in the gear 56 so asto permit the worm 58. to rotate idly without driving the gear- 56 when the shaft 51 has attained. its minimum speed position.

The speed control appartus is automatically restored upon reenergization of the control relay -K'. This supplies current to the cam-starter magnet 61, which raises the shaft 57 and disengages gears 56 and 58, so that the shaft 51 and its cams may return to the normal or initial position under the influence of the counterweight 56 It is contemplated that suitable devices,

similar to those disclosed in my prior application, Serial Number-65,071, filed Decemable warning signal a sufficient time before the automaticzapplication of the brakes occurs to permit him to apply the brakes himself. lVhen such a warning signal/is used it is practical to hold the engineer or motorman strictly accountable for any automatic application of the brakes which may occur since he is informed by the lighting of the yellow lamp that he should proceed cautiously and is further advised by the warning signal when he should immediately commence to reduce the speed of his train. WVith the aid of the illustration and description in myprior application above mentioned, the addition or application of the warning signal to the parts of the system shown and described is considered to be within the ability of one skilled in the art of railway signaling; and to avoid confusion and complication this warning signal has not been shown.

provision is made to prevent automatically the train from attaining a speed greater than a maximum perm ssive speed, even II.II..

though there may be a clear track ahead of the train. Referring to Fig. 2, it can be seen that even though the cam'55 1s stationary in its normal position, the speed arm 46 cannot be moved to the left through more than a certain angle without causing separation of the arm 49 from contact stud 45 of the corresponding'arm 43, since the roller 48 of the speed arm 46, after th1s arm has moved through a certain; angle counterclockwise, strikes the edge of the corresponding cam 55; In other words, when the cam 55 is in its normal position, the actual speed of the train cannot exceed a certain amount without causing an automatic application of the brakes in the same way as occurs Whenthe actual speed of the train exceeds its permissive speed. The same effect is produced it the speed of the train is being controlled by the can] 54. It should be noted that the cams 54 and 55, corr spond to blocks of different lengths havingdifierent curves of permissive speed, and" are in practice shaped differently so as to impose different limitations upon the maximum speed which the train may attain when traveling under a proceed signal with a clear track ahead. In the particular construction illustrated, this resultis accomplished by making the radius of one cam, namely, the cam 54, to the point marked 00 greater than the corresponding radius of the other cam 55, so that the arm 47, which is assumed to be in the same a plane with the arm 46, cannot move counterclockwise as far as the arm 46 can move before the roller 48 strikes the edge of the cam 54; but obviously the same result may be obtained in other ways.

By reason of the features of the construction just described, the train in any one block cannot attain a speed greater than the maximum permissive speed prescribed for it by the cam corresponding to that block. This limitation upon the maximum speed which the train may attain in the block while traveling under a proceed signal not only makes it possible to restrict the speed of a train in any given portion of the track to a speed proper to safety, but also makes it practicable to regulate the speed of a train in any one block so that the train, when it leaves that block and. enters the next block. cannot be traveling so fast that its speed cannot be safely governed in this next block. To illustrate, referring to Fig. 1, a train in the block A cannot attain a speed greater than the speed indicated by the line 7 Con- Sequently the speed of the train when it enters the block B cannot be greater than the maximum permissive speed for the block B, so thatthe speed of the train may be reduced in accordance with the curve of permissive speed for the block B by the time the train reaches the end of the block C, if the traffic conditions require such a reduction in speed.

memos The same safety is obtained where the block having .a low maximum permissive speed is followed by a blockhaving a high maximum permissive speed, since it is apparent that when the train leaves the first block and enters the second block, it must necessarily be traveling at a speed less than the maximum permissive speed of the second block. Such a condition is indicated in Fig. 1, where the blocln E is followed by the blocks F and G, the .maximum permissive speed for the block E being lower than that for the combined blocks F and G. In practice it is probable that a train after l'eaving the block E Would accelerate as indicated by the dotted line designated 200. The same principle does not hold true, however, where a block having a high maximum permissive speed .is followed by a block having a lower maximum permissive speed. Such a case is illustrated in Fig. 1 where the combined blocks B and C are Succeeded by theshorterblock D having a lower maximum permissive speed; and from Fig. 1 it can be seen that if a train in the combined blocks B and C were allowed to continue at the maximum permissive speed indicated by the line 7, this train might enter the block D at such a high speed that even though the brakes were immediately applied, it could not be brought to a stop or to a predetermined low speed by the time it reached the end of the block D. For this reason it is not permissible to permit a train to maintain the same maximum permissive speed throughout the lengths of the blocks B and C; but on the contrary it is necessary to compel the train to reduce its speed in the block C so that when it enters the block D, it will not be traveling at a speed greater than the maximum permissive speed of the block D. Moreover, this reduction of speed in the block C should occur regardless of whether the train is traveling under the proceed signal or caution signal. The reduction of speed in the block C is accomplished automatically by setting the safety control apparatus into operation upon each train every time it enters the block C so that the train is compelled to follow the curve of permissive speed indicated in Fig. 1 for the block C, which, as can be seen from the curves in Fig. 1, intersects the vertical line (i at a point indicating substantially the same speed as the maximum permissive speed of the block D.

Trackwa y circuits.

rangement of the trackway circuits shown in Figs. 3 and 4 whereby the voltages supplied to the different ramps are controlled in ac cordance with the trailic conditions so as to produce the proper.controllin g'etfects on the train. In giving this description of the trackway circuits, is considered sufiicient,-infl view of the foregoingdescription, to merely trace the diiterent circuits set up along-- the track under different traific .condi-'" tions, and state briefly the action produced on the speed control apparatus on the train. Referring to Fig. 3, assume that a train is approaching the entrance .to the'kblock A, and that no dangerous conditions exist in either the blocks A, B or C. Under these" conditions the track relays 9, 9 and '9 of the respective blocks A, B and C are energized, and their respective armatures are in their upper position as shownin Fig. 3. Asthe Q train in question proceeds. and'the firstco'ntact shoe carried thereby'engages'the ramps RA, the parts of'the speed control apparatus are restored to: their normal position, if. they are not already there; "and" are held in their normal position, by reasonof the high difierence of potential existing between the ramp RA and the track rail 1, due to the following partial circuit:

Commencing at the ramp RA, conductor 166, armature 10 of-the track relay 9 in its upper position, conductor 167, batteries 14,- 15 and 16 in series, and conductor 168,

I back to the track rail 1.

As the train in question progesses and its first pair of wheels and axle enter the block- A, the track relay 9 is shunted and its arma:

ture drops.- The partial circuit for the ramp RA is t en along conductor166, armature 10 of the track relay 9 in its lower position,

along the conductor 169 leadingaheadto the armature 11 of the trackrelay 9 in its upper position, thence along conductor 170, armature 12 of the track' rela 9 in its upper position, conductor 171 t rough the batteries 14? and 15 in series,'and conductor '17? to the track rail 1.

mentioned train enters the block A, that another train occupies the block B. ,Under this condition, the track r'ela '9 is deenergized and its armature 11 18 111 its lower position and connectsj'the' ramp RA to a low: voltagesource of current by partial circuit 'as follows:

Y, Commencing at the ramp RA, conductor 166, armature 10 of the track relay 9 in its. lower position, conductor .169, armature 11 ofthetrackrelay-=9 in its'lowerposition, I

conductor-12,112, -fbaaer 14 and conductor 173' to the trackr'ail 1.

potential, while it This low difference of v maintains the, stopi-relay S' sufiicientl-y energized ,toits-' armature's in their upper position,,resuI-t s the dro ping of the armatures ofthe control relay so as'to change the proceed signal .tothecaiution signal and set the cam 55, corresponding-to the block A, into motion so as to compel a reduction. inthe speed of the first mentioned train corresponding to the curve of permissive speed or the block A. It is contemplated that the motor-man .or the engineer of the; train, aided possibly by some other before referred to, will ordinarily obey the cautioni'signal and control-the speed of his 't i ii 'ft J application ofi the- .brakes is; necessary,"

e fblock fA so: that an automatic means, such as the warmngsignal hereinbut'it is apparentfthat' if themotorman or 1 the engineer. fails runn reason to perform his duty thespeed of the train will be controlled automatically. While it is possible by properly shapin the cam 55 to bring the tram'to a comp ete sto reaches the end of the .blo'c' A,'-- the partic-. ular-embodiment "of the" invention illus trated is designed with a view of bringing the train to a"certain predetermined low] speed atthe end of the block, A for the reason that practical operating requirements 95. by 't'he time it seem to be satisfied without bringing the train to a complete stop; 7.

- For the next illustration, assume that when' the train first referred to enters the block A, the blockC is occupied by another train. Under these conditions the "armature 12 of the track relay'9 bein inits lower position connects the ramp A with the battery 14 and by reason of this low difference of potential between theramp' RA and the track rail 1, the speed control apparatus is set into operation.

It should be noted that the combined length of the blocks B and C is assumed to ual to the length of the be substantially er words, the curves of 8 block A; or, in ot permissive s eedare the same for the blocks.

B and C ta en together as for the block A alone (see Fig. 1-). For this reason it is necessary to make the partial circuit establishing-a medium difference of potential be- "tween the ramp RA and the track rail 1 dependent u on both of the track relays 9 and 9. 'I his' condition, in'which the conltr'olling circuit for the ramp is controlled byt he track relays of the two blocks in adtime the first mentioned train reaches theend of the block A, the other train formerly in the block C has entirely moved into block D. By the time the first mentioned train reaches the entrance of the block B and its first contact shoe engages the ramp RB, it will be travelin at the predetermined low speed hereinbjore described; but since neither of the blocks B nor C is occupied, that is,there is a full braking distance between the first mentioned train and the next train in advance, it is permissible for the first mentioned train to accelerate and move through the blocks B and C as fast as the curve of permissive' speed for these blocks.

allows. In the system embodying this invention, this result is accomplished by resetting or restoring-the parts of the speed control system to their normal position at the ramp RB, this being attained by establishing a high difierence of potential between the ramp RB and the track rail 1 by a partial circuit as follows:

Commencing at the ramp RB, conductor 178, armature 10 of the track relay 9 in its upper position, conductor 179,'armature 10 o the track relay 9 in its upper position,

conductor: 180, batteries 14 15 and 16 in series, and conductor 177to the track rail 1. After the first mentioned train actually enters the block B,the difference of potential between the ramp RB and the track rail 1 is dependent upon the condition of the block in advance, as the block D. If the block D is not occupied by a train, the armature 11 of the track relay 9 is in its up-- per position, and connects both of the batteries 14 and 15 by conductors 178,181, 182 and 183 to the ramp RB, thus establishing a medium difference of potential between the ram BB and the track rail 1. However, if t e block D is occu ied In another train,,the armature 11 of t e trac relay 9 is in its lower osition, and connects the ramp RB by con uctor 185 to the battery 14 alone, thus establishing a low difference of potential between the ramp RB and the track raill. In this way, if the block D is occupied, the speed control apparatus of the first mentioned-train enter1ng the block B is set into operation; whereas it the block D is not occupied-the speed control apparatus of the first mentioned train remains in its normal position.

Change from long block to'short bl oclc.

" at some intermediate point, this point being in this particular instance at the entrance of the block C. In fact, it may be said that the length of the block C is determined with reference to the maximum permissive speedsof the block D and of the blocks B andv C, so that if the speed control apparatus .on a train travelingat the maximum permissive speed in the block B is set into operation at the entrance tothe block C, the eed of this train at the entrance to the bloc D will not exceed the maximum permissive speed for the block D. In order that the speed control apparatus may be set into operation on each train when it enters the block C, the ramp RC is directly connected by means of conductors 186, 174 and 175 to the battery 14 or, in other words, a low 'difterence'of potential exists at all times between the'ramp RC and the track rail 1' regardless of trafic conditions. In this connection it should be noted that it is necessary to have a low difference of potential-between the ramp RC and the track rail 1 in order to prevent the emergency application of the brakes; and in systems where the emergency application ot the brakesis dispensed with, as shown n Fig. 5, or in cases where the emergency application is produced in some other way, it is possible to have the ramp RC totally disconnected from any source of current, as shown in Fig. 6.

Control for fixed hazards.

Referring to thepart of the track including the" blocks D and E, this arrange-" ment is assumed in order to illustrate the control of the speed of a train on the approach to, or -by a fixed hazard, assharp.

curves. The sharp curves. in the blocks D and E make it desirable to. require that the permissive s eed which a train may attain here that the conditions just explained illustrate one necessity for having the blocks of a railroad of different lengths. According to this invention allowance is made for the comparative low maximum permissive speed 'for the blocks D and E for the shorter length of these blocks by using a cam, as

actuated by the selector-ramps SR, SC and SL. In the particular arrangement shown, the selector tappet 74, which is actuated by the right hand selector ramp SR controls the selection of thecam 54; whereas the selector tappet 76 actuated by the left hand selector ramp SL, controls the selection of the cam 55. \Vhile a train is traveling through the blocks A, B and C, the cam 55 on that train is effective, and the selector relay 81 controlling that cam is maintained energized by the middle selector tappet 75. Near the entrance to theblock D are arranged a middle selector ramp SC and a right hand selector ramp SR; and when a train passes these selector rainps the selector tappets 74 and 7 5 are raised. \The raising of the middle -selector tappet 75 interrupts circuit Number Seven which maintains the selector relay 81energized, and since the selector tappet 7 6 is in its lower postion and the circuit Number Six is interrupted, the selector relayv81 is deenergized and its armatures drop 'At the same time the raising' of the selector tappet 74 closes circuit Number Nine and energizes the selector relay 80. The right hand selector ramp SR v is made longer thanthe middle selector ramp SC, as shown in Figs. '1 and 3, so that before the selector tappet 74 returns to its normal lower position and interrupts the circuit Number Nine, the middle selector tappet 75 leaves engagement with the middle selector-ramp SC and in returning it to its normal position closes the circuit Number Ten which maintains the selector relay 80 energized. While the'selector relay 81 is energized, the electrically operated valve SB,

controlling the service application of the breaks, is controlled by the cam 55 through circuit Number Eight; but while the selector relay 80 is energized, said valve SB is controlled by the cam 54 through circuit Number Eleven: As explained hereinbefore, the cam 54 is shaped to compel the train to keep below a maximum permissive speed which is lower. than the m ximum permissivev speed for theblock A; and the cam 54 remains efie'ctive to'control the s until the train reaches t e. selector ramps d of;v the train block E, whereupon the middle selector'ramg SC raises the middleselector tappet 75 an interrupts the circuit Number Ten, the left hand selector ramp SL at the same time raising the selector tappet 76 to close the circuit Number Six, so that when the selcctor .tappet returns to its lower position, it'

closes circuit Number Seven and maintains the selector relay 81 energized. In, this way the control of the speed of a train is shifted from the cam 54 back again to the cam'55.

For the control of a trainby fixed hazards as around sharp curves and the like, it is desirable that the train should not be allowed to accelerate until the last car thereof has completely passed the fixed hazard. These advantageous results may be easily obtained according tothis invention proviuing a train is equipped with a locomotive or motor car at each end, each of said locomotives or motor cars being equipped with a speed control apparatus, since the speed of the train as a whole cannot be increased until the last locomotive or motor car has passed the selector ramps SC and SL at themtrance to the block F, and until the train has wholly passed the fixed hazard its speed will be kept below the maximum permissive speed imposed by the cam corresponding to the blocks adjacent to the set fixed hazard. Similar results may be accomplished in the case of a train having a locomotive or motor car at the front end only by locating the blocks D nor E is occupied. Under these conditions until a train enters the block D a high difference of potential exists between the ramp RD and the track rail 1 according to a partial circuit as follows:

'Commencing at ramp RD, conductor 187, armature 10 ofthe track relay 9 in its up per position, conductor 188, batteries 14, 15 and 16 in series, and conductor 184 to the track rail 1.

I When the train actually enters the block D, the track relay 9? is shunted and deenergized, and remembering that it is assumed that'the block E is not occupied, a medium difierence oi potential, which keeps the parts of the speed control apparatus in'their normal position, is established between the lamp RD and thetrack rail 1 by a partial ircuit, as follows:

Commencingat ,theiramp RD, conductor 187,- armature l0 -of the track relay 9 in its. 

